The on-site bio-energy plant commissioned one year ago by Diageo at its Glendullan distillery in Speyside is helping lead the Scottish whisky industry’s drive for environmental sustainability and carbon reduction.
The Clearfleau anaerobic digestion (AD-power) plant has delivered a 25% reduction in fossil fuel energy demand at the distillery, saving Diageo significant costs and reducing its carbon footprint by 1,000 tonnes of CO2 per year.
Over the past 12 months, anaerobic digestion at the Dufftown distillery has converted approximately 1,000m3 per day of malt whisky distillery co-products into renewable energy. This is about 1 million m3 of biogas per year – producing 6000 MW hours of thermal energy for the distillery.
Diageo and Clearfleau collaborated in developing the bio-energy plant at Glendullan and the initial plant at nearby Dailuaine distillery that has been operational for over three years. Each on-site plant comprises a high-rate digester, specifically designed to handle liquid distillery co-products, followed by aerobic treatment for water clean-up.
The AD plants reduce the incoming COD load by over 95% and minimise further treatment required for the discharge of cleansed water to nearby rivers.
It will help meet the Scottish Environment Protection Agency’s new plans for enhanced resource use – achieving low carbon emissions, improved materials use and energy savings.
It will also enable local farmers to replace fossil-fuel-derived fertiliser with nutrient rich bio-solids.
Digestion of distillery residues is making a major contribution to Scottish targets for both carbon mitigation and the generation of renewable energy. The net carbon savings for the two plants, based on replacement of aerobic treatment with the innovative anaerobic bio-energy solution deployed at Dailuaine and Glendullan is about three tonnes of carbon a day.
Craig Chapman, Chief Executive of Clearfleau, said: “With the distillery sector setting tougher sustainability targets, SEPA’s beyond-compliance ‘one planet prosperity strategy’ endorses practical action, such as optimising energy output from unwanted co-products“.